yea honestly a 500 dollar dh bike is gonna be more trouble than its worth. you'll probably spend more time/money repairing and upgrading it than you will riding it. I'd work for another month or so and try to save up some more, it'll be way worth it.
"My penis isn't even that big I don't think." -Itsbackfliptime
get his bike. it might take maybe $50 to get it running good as new. it looks like he needs a chain and a bashguard. (bashguards are metal or plastic rings that you bolt on to the chaingring so you dont chew up your gears on rock and stuff.